1. Field of the Invention
The present invention relates to an apparatus for rejecting articles from a press conveyor to an upstacking device.
2.Description of the Related Art
Metallic closures for cans and the like are often formed in a rapid metal stamping operation. In general, closures are transported by a transfer belt to various stations for shell forming, tab forming, etc.
It is well-known in the art to transfer finished closures from the transfer belt at an upstacking station. The transfer belt is stopped and a reciprocating member moves upward through an aperture in the belt and pushes the closure upward into the upstacking station. The reciprocating member then moves downwardly to a position below the transfer belt and the belt is advanced forward for the next operation.
U.S. Pat. No. 4,390,098 issued to Wilgus et al. discloses an apparatus for automatically rejecting closures from an upstacking device. A variable length reciprocating member selectively pushes closures from a transfer belt into a closure receiving means. The reciprocating member is a double acting pneumatic cylinder by a lever and pivot arrangement. In the reject mode, the variable length member is retracted so that it does not contact a closure. All rejected closures continue to travel along the conveyor and fall into a bin.
Particularly at high speed operations, prior art reciprocating members have a tendency of catching and hanging onto the transfer belt. If a reciprocating member fails to retract below the belt, the member will remain in the belt aperture, resulting in belt tearing as the belt is advanced.
In high speed presses, a short press stroke is employed. This stroke is usually in the range of 11/2" to 2". This short stroke does not provide sufficient space, when the press ram is fully retracted, to gain access to the tooling for maintenance purposes. To offset this disadvantage, press manufacturers incorporate a hydraulic or mechanical system to allow raising the ram an additional two or three inches to provide tooling access.
In conventional upstacker/reject systems, such as disclosed in U.S. Pat. No. 4,390,098, the attachment to the ram must be disconnected before the ram is raised for tooling maintenance. If it is not disconnected, damage to the upstacker/reject system occurs since it is designed for movement within the confines of the press stroke only.
Consequently, a need exists in improvements in upstacker rejecting devices for conventional presses. It is desirable that upstacker reject devices provide dependable operation in high-speed operations. Furthermore, it is desirable that such a reject device include means to insure that the reciprocating member is retracted below the transfer belt before the belt is advanced. Also, an improved upstacker should permit automatic disengagement when the ram is retracted to gain access to the tooling for maintenance.